master mix in STP

Hi, I have all the tracks lined up for this movie, but I can't figure out what I'm doing wrong trying to get a master mix. Nothing's soloed or muted, but when I press record, nothing records. Can ya hep me? Thanks, Frank

That is, I don't know how to do a Master Mix. And I can't find an explanation. It's one of those things considered "self-explanatory", maybe.

Let's see, I moved from preserve to encode, and that gave me the option to use H264, which I saw had been the compression used in the .mov file sent to me for music. So now it says it will take 6 hours, so that sounds right for 90 minutes, right?
I just pray when we get there that the audio will be included... F.

I never did find any master mix, so I just went to Export..

Well, I thought I had it on the run, but after 9 hours it failed. IS there such a thing as a master mix that you need before you export, or do you just stick your video in the Compressor box, select QT H.264
and a destination, and leave the tracks automated to be compressed with the video? I don't get it. thanks, Frank